​​​(Toronto, May 10, 2023) – While severe outcomes from COVID-19 have decreased with each new wave, a new study suggests the risk of cardiovascular (CV) hospitalization has persisted or increased – particularly for younger men, aged 18 to 45. The study was conducted by the Peter Munk Cardiac Centre at the University Health Network, ICES, and Women's College Hospital.

Studies around the world have pointed to male sex, old age, and pre-existing health conditions as independent risk factors for increased severity of COVID-19 infection, disease and death.

"Initially, interactions between sex and certain health conditions were found to have a greater impact on women, who were more likely to experience severe outcomes like intubation or death," says Bahar Behrouzi, MD/PhD candidate at the University of Toronto, and study lead. "But there was no analysis yet of possible sex differences by age for severe outcomes, particularly in North America, that honed in on cardiovascular hospitalization."

The retrospective cohort study, published in JACC: Advances​, included almost all patients in Ontario with laboratory-confirmed SARS-CoV-2 infection during the first three waves.

The study showed that across all waves and in all age groups, men experienced higher rates of a severe outcome (e.g., requiring hospitalization for a cardiovascular complication, intensive care, a breathing machine, or dying) compared with women, although the magnitude varied by age.

While the difference between men and women in the risk of all-cause death was highest during Wave One – with young men at four-fold higher risk – younger men and women were at similar risk by Wave Three, which could be due in part to vaccinations and non-pharmaceutical interventions.

However, for CV hospitalization, with each subsequent wave, there was little to no change in the increased risk borne by men versus women for all age groups. In general, across all waves, middle-aged men (ages 46 to 65) were at two- to three-fold higher risk compared to women of the same age.

"We know that adopting an age- and sex-informed approach to patient care has improved outcomes," says Dr. Jacob Udell, cardiologist and clinician-scientist at the Peter Munk Cardiac Centre, ICES, and Women's College Hospital, University of Toronto, and principal investigator of the study. “Accounting for this variation in risk is especially crucial in early decision-making for patient treatment. Our findings suggest that in the first month after a positive COVID-19 test, patient care should be tailored to better prevent cardiovascular events, particularly among younger men."

The findings highlight the need for further efforts to examine clinical, biological, psychosocial, and health system factors contributing to the growing disparity between the sexes in the risk of cardiovascular hospitalizations following COVID-19.

The study, "Sex-based differences in severe outcomes, including cardiovascular hospitalization, in adults with COVID-19 in Ontario, Canada" was published in JACC: Advances.

About Peter Munk Cardiac Centre (PMCC)

Opened in 1997 through the generous support of Peter and Melanie Munk. A global leader in cardiovascular care, with internationally-renown medical expertise, PMCC has some of the best patient outcomes in the world and is home to many world firsts that span cardiac and vascular research and discoveries. Canada's premier cardiac centre is part of the University Health Network, and is located at the Toronto General Hospital, and the Toronto Western Hospital, in Toronto, Ontario, Canada. For more information, visit: www.petermunkcardiaccentre.ca

About ICES

is an independent, non-profit research institute that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. In October 2018, the institute formerly known as the Institute for Clinical Evaluative Sciences formally adopted the initialism ICES as its official name. For the latest ICES news, follow us on Twitter: @ICESOntario

About University Health Network

University Health Network consists of Toronto General and Toronto Western Hospitals, the Princess Margaret Cancer Centre, Toronto Rehabilitation Institute, and The Michener Institute of Education at UHN. The scope of research and complexity of cases at University Health Network has made it a national and international source for discovery, education and patient care. It has the largest hospital-based research program in Canada, with major research in cardiology, transplantation, neurosciences, oncology, surgical innovation, arthritis, vision, infectious diseases, genomic medicine and rehabilitation medicine. University Health Network is a research hospital affiliated with the University of Toronto. For more information: www.uhn.ca

About Women's College Hospital

For more than 100 years Women's College Hospital (WCH) has been developing revolutionary advances in healthcare. Today, WCH is a world leader in health equity and Canada's leading academic ambulatory hospital. It focuses on delivering innovative solutions that address Canada's most pressing issues related to population health, patient experience and system costs. A multidisciplinary research institute, the Women's College Research Institute (WCRI) is one of only a few hospital-based research institutes worldwide to focus on health equity. WCRI leads innovative, high-impact health research that changes practice, changes policy, and changes lives. www.womenscollegehospital.ca

Media Contacts​

Misty Pratt
Senior Communications Officer, ICES
Email: Misty.Pratt@ices.on.ca
Phone: 613 882 7065

Jordan Benadiba
Manager, Public Affairs, WCH
Email: Jordan.benadiba@wchospital.ca
Phone: 647 248 3680

Courtney Mahrt
Senior Public Affairs Associate, UHN
Email: Courtney.mahrt@uhn.ca
Phone: 437 217 2819

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